1. Field of the Invention
The invention relates to a flame barrier made of nonwoven fabric for use, e.g., as a component of an automobile or aircraft passenger seat, the seat consisting of a back surface of a foam, the flame barrier, and, on the visible side, a top material.
2. Description of Related Art
Automobile and aircraft passenger seats are suitable for installation in public conveyances on water, on land, and in the air. Aircraft passenger seats, in particular, are subject to strict regulations in terms of fire characteristics.
U.S. Pat. No. 5,279,878 (Fottinger et al.) describes a flame barrier made of nonwoven fabric as a component of a planar multilayer structure, for example a seat. Despite its efficiency according to standards ISO 8191-1 and 8191-2, it has a weight per unit area of no more than 100 g/m.sup.2 down to 40 g/m.sup.2, and possesses a textile drape, wear comfort, and good formability. Its thickness is a maximum of 1.8 mm, and its strength at least 10N/5 cm.
These properties are achieved by the fact that the nonwoven fabric consists of partially graphitized polyacrylonitrile fibers with an LOI value of at least 40; that it is bonded with water jets at a pressure of 10,000 kPa to 14,000 kPa; that its fibers have no flameproof impregnation; and that it additionally contains reinforcing elements, incorporated in a warpwise/weftwise arrangement, in a proportion of 12 to 60 g/m.sup.2.
Exemplary applications for this flame barrier are low-flammability garments, interior fittings of the passenger area of air, land, and waterborne vehicles, engine compartment interior linings, upholstery materials, textile interior furnishings, cushions, and mattresses.
However, flame barriers of this type do not satisfy the terms of the aircraft industry's requirements for aircraft passenger seats, as set forth in FAR 25.853 (b), Amendment 25 to 59. Compliance with this regulation of the Federal Aviation Administration, Department of Transportation, is tested and verified on a simplified seat structure: a seat cushion and back cushion are constructed horizontally and vertically with all the upholstery materials representing the seat (foam core, filler material, fire blocker, seat covering fabric, seams). A flame is applied to this seat structure for two minutes using an oil torch. Flame temperature is 1038.degree. C. Test criteria are a maximum weight loss of 10% during the test period, and maximum flame lengths, as measured from the edges, of 17 inches (432 mm). Flame energy is 119 kW/m.sup.2, and flame distance is 102 mm.